This invention relates to a Hybrid High Integrity Pressure Protection System (H-HIPPS) for severo services, the hybrid system includes a quick isolation subsystem between an overpressure zone and a normal pressure zone and a quick releasing subsystem between the overpressure zone and a lower pressure zone with quadruple redundancies for 30 year service without repair, more particularly, the hybrid system has a novel valve and a novel pilot, each with two independent plugs with metal to metal seal (buckling seal) B ring assemblies and a novel (attachable) A seal ring assembly to block or release over pressurize fluids without actuators for protecting the pipelines or the pressures vessels from surge pressure at the highest level of a system reliability, the quick releasing subsystem has novel hybrid and redundant pressure relief mechanisms, redundant pressure sensing mechanisms and secondary pressure surges depressor, cavitations and erosion suppression and detect mechanisms, while quick isolation subsystem has redundant closures members and cavitations reducer can be used for a control valve or pressure regulator with the best both static and dynamic performances, in most cases, two valves are used, one for isolating fluids, one for regulating the fluids.
When pipelines or pumping stations or piping terminals, pressurized fluids plants are in services, many times, the operations like open and closing, pumping and metering can cause water hammer and pressure surge, the pressure surge in pipelines or plant can cause many problems as following; (a) Axial temporal and permanent separation of flange joints (b) Pipe fatigue at weld joints (c) Longitudinal pipe splits (d) Severe damage to piping and piping supports (e) Severe damage to elbow (f) Pipe leak (g) High cost for constant repair (h) inaccurate metering due to leaks in supply stations (i) environmental pollution.
There are two solutions for the problem (1) to block the overpressure fluid zone into a normal pressure zone or (2) to release the overpressure fluid into a low pressure zone, the conventional quick blocking subsystems like HIPPS based on API 17O is equipped with two shut off valves, two actuators and pressure transmitters and a feedback control system, but this subsystem at this point is just a combination of conventional parts like valves, actuators and pressure sensors and controller at a lower system reliability and is constructed under overpressure class at least three time in overpressure fluid zone even for a short period time and waste lot of materials and capacity in normal pressure conditions, so far there is no single valve or actuator, which are developed for the high integrity system, while the conventional quick releasing subsystem is constructed as overpressure safety device under U.S. Department of Transportation, Pipeline Safety Regulations, Hazardous Liquids Part 195, paragraph 195.428, the subsystem includes the pressure surge relief valve s like plug axial pressure surge relief valves, those valves are widely used in the pipeline protection from pressure surge and constructed with main three functions sensing, tracking and releasing, the plug axial pressure surge relief valves have two types, a gas loaded and a pilot operated configurations, the gas loaded pressure surge relief system has a fast response time about 250 millisecond, but it is equipped with external energy resources like pressurized bottle nitrogen, pressure regulator, check valve, tubing, insolated plenum bottle and control boxes, the subsystem not only increase cost and reduce a system reliability and sensible to temperature swing, but also has high operation cost to remain the set pressure with high cavitation and erosion, while the pilot relief system is operated by internal fluid energy with a compact pilot, but the pilot has a remote pressure sensing function and slow response time about two second or more and is less tolerated with dirty fluid and unreliable, every pressure releasing causes 10 to 30% pressure or energy loss and with high cavitation and erosion, in short the both type subsystems have no redundant system and cannot provide a good seal at low temperature, or high temperature and have high blow down pressure up to 30% and waste significant fluid energy and need constant seal goods replacements.
So the flow control industry has long sought means of improving the performance of the pressure protection valve and systems valve, improving the seal, creating a robust hybrid, enabling the valve to handle various flows under multiple extreme conditions.
In conclusion, insofar as I am aware, no such a system is formerly developed with fully metal to metal seal, hybrid highly reliable pressure protection system, easy manufacturing at low cost, they can be used for blocking and releasing overpressure fluids in sever service.